Cinema screens are typically made of perforated cloth for letting sound through, and typically have a thick texture that reflects the direct light of the projector. Typically, only the screens of the back-projectors are transparent to let the light rays coming from behind the screen pass through. This back-projector technology generally does not allow for large screen surfaces to be obtained.
Two observed natural phenomena oblige us to take into account the facts that, first, all objects absorb a portion of the light and reject the visible non-absorbed colors and, second, ambient light comes from all sides, including from behind the object with all the incidence degrees of light diffractions reflected therein. These two facts form the motivation for the present patent application filing.
In practice, the use of a multitude of light sources as a background for the screen makes it possible to re-establish a natural light balance that may not exist on current cinema screens. PCT application No. FR2006/000073 describes the use of a multi-layer screen of which the bottom layer of the multi-layer screen is a highly reflective surface including, for example, of a sheet of micronized aluminum or vacuum-sputtered aluminum or silver. The bottom layer is translucent, and the other layers are translucent or transparent.
The assembly greatly increases the light diffractions of the projector. The effect is reinforced, if necessary, by transparent micro-droplets or micro-balls placed between the layers of the multi-layer screen.
The screen is produced with metalloplastic films, which are relatively thin and allow through and filter a low soft diffuse light intensity through the silvered or aluminized bottom film. This principle of light sources added behind the screen adds a “contre-jour” or backlighting effect that may be important for the light quality of the images. More particularly, it may be important to obtain an image having a real natural balance of the colors and of the perspective forms of the objects.
In practice, the stable backlights bring visual comfort and a chromatic stability that greatly amplify the diffractions. The chromatics and density of the lights are regulated by this principle, which is made possible by the translucent bottom layer, and the backlights, which may give a projection that conforms to the optical sensitivity of the eye and of the nervous system. The projection is non-aggressive.
Contrast variations may not be useful, whereas the quantity of information on sensitive variations of all the lights is typically vital. The significant quantity of soft variation of the light is more effective than the variation of intensity of the aggressive contrasts of hard direct light from the projector, which stains the image and tires the sight.